Critique my mismatched Teen Build.

When it comes to people saying don't run large port heads, I believe that's trickle down from engines like the tunnel port 302's and such. 273 heads where designed for a 273 and 340 heads where designed for a 340, 318 and 360 didn't have any heads designed for them until the magnum and when 318 was built the only head being produced was the 273 which is fine for a low powered 318. But 318's are closer in size especially when over bored to a 340 than a 273.

I was thinking the same head and cam combo if I go 318.
While your cam choice leaves power on the table it all depends what your after. For my 400 ford I picked a small cam comps 255deh cause with headers, performer intake and carb, bowel work and that cam I'd figured it would double the stock power output which is more than enough for the bronco and I know I could easily go bigger but I'm not willing to give up even a 1/2 mpg for even 20 or more hp. But for your build I would go with the solid cam a 318 with those heads will love rpm and smaller engines hp curve tapper off slower than larger engine giving you more of a usable powerband (rpm).